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Robert D. Schopp

Publications and source records attributed to Robert D. Schopp.

7 recordsLinked to original sources
USGS2009

Methodology for Estimation of Flood Magnitude and Frequency for New Jersey Streams

Methodologies were developed for estimating flood magnitudes at the 2-, 5-, 10-, 25-, 50-, 100-, and 500-year recurrence intervals for unregulated or slightly regulated streams in New Jersey. Regression equations that incorporate basin characteristics were developed to estimate flood magnitude and frequency for streams throughout the State by use of a generalized least squares regression analysis. Relations between flood-frequency estimates based on streamflow-gaging-station discharge and basin characteristics were determined by multiple regression analysis, and weighted by effective years of record. The State was divided into five hydrologically similar regions to refine the regression equations. The regression analysis indicated that flood discharge, as determined by the streamflow-gaging-station annual peak flows, is related to the drainage area, main channel slope, percentage of lake and wetland areas in the basin, population density, and the flood-frequency region, at the 95-percent confidence level. The standard errors of estimate for the various recurrence-interval floods ranged from 48.1 to 62.7 percent. Annual-maximum peak flows observed at streamflow-gaging stations through water year 2007 and basin characteristics determined using geographic information system techniques for 254 streamflow-gaging stations were used for the regression analysis. Drainage areas of the streamflow-gaging stations range from 0.18 to 779 mi2. Peak-flow data and basin characteristics for 191 streamflow-gaging stations located in New Jersey were used, along with peak-flow data for stations located in adjoining States, including 25 stations in Pennsylvania, 17 stations in New York, 16 stations in Delaware, and 5 stations in Maryland. Streamflow records for selected stations outside of New Jersey were included in the present study because hydrologic, physiographic, and geologic boundaries commonly extend beyond political boundaries. The StreamStats web application was developed cooperatively by the U.S. Geological Survey and the Environmental Systems Research Institute, Inc., and was designed for national implementation. This web application has been recently implemented for use in New Jersey. This program used in conjunction with a geographic information system provides the computation of values for selected basin characteristics, estimates of flood magnitudes and frequencies, and statistics for stream locations in New Jersey chosen by the user, whether the site is gaged or ungaged.

Scientific Investigations Report↗
USGS2008

Flood Magnitude and Frequency of the Delaware River in New Jersey, New York, and Pennsylvania

From September 2004 to June 2006, the Delaware River in New Jersey, New York, and Pennsylvania experienced three major floods that caused extensive damage. The Federal Emergency Management Agency (FEMA) needed updated information on the flood magnitude and frequency for the eight active streamflow-gaging stations along the main stem Delaware River in New Jersey, New York, and Pennsylvania that included the three recent floods in order to update its flood insurance studies. Therefore, the U.S. Geological Survey (USGS) computed updated flood magnitude and frequency values following the guidelines published by the Interagency Advisory Committee on Water Data in its Bulletin 17B. The updated flood-frequency values indicate that the recurrence interval of the September 2004 flood ranged from 20 to 35 years, the recurrence interval of the April 2005 flood ranged from 40 to 70 years, and the recurrence interval of the June 2006 flood ranged from 70 to greater than 100 years. Examination of trends in flood discharges indicate no statistically significant trends in peak flows during the period of record for any of the eight streamflow-gaging stations.

Open-File Report↗
USGS2005

Streamflow characteristics and trends in New Jersey, water years 1897-2003

Streamflow statistics were computed for 111 continuous-record streamflow-gaging stations with 20 or more years of continuous record and for 500 low-flow partial-record stations, including 66 gaging stations with less than 20 years of continuous record. Daily mean streamflow data from water year 1897 through water year 2001 were used for the computations at the gaging stations. (The water year is the 12-month period, October 1 through September 30, designated by the calendar year in which it ends). The characteristics presented for the long-term continuous-record stations are daily streamflow, harmonic mean flow, flow frequency, daily flow durations, trend analysis, and streamflow variability. Low-flow statistics for gaging stations with less than 20 years of record and for partial-record stations were estimated by correlating base-flow measurements with daily mean flows at long-term (more than 20 years) continuous-record stations. Instantaneous streamflow measurements through water year 2003 were used to estimate low-flow statistics at the partial-record stations. The characteristics presented for partial-record stations are mean annual flow; harmonic mean flow; and annual and winter low-flow frequency. The annual 1-, 7-, and 30-day low- and high-flow data sets were tested for trends. The results of trend tests for high flows indicate relations between upward trends for high flows and stream regulation, and high flows and development in the basin. The relation between development and low-flow trends does not appear to be as strong as for development and high-flow trends. Monthly, seasonal, and annual precipitation data for selected long-term meteorological stations also were tested for trends to analyze the effects of climate. A significant upward trend in precipitation in northern New Jersey, Climate Division 1 was identified. For Climate Division 2, no general increase in average precipitation was observed. Trend test results indicate that high flows at undeveloped, unregulated sites have not been affected by the increase in average precipitation. The ratio of instantaneous peak flow to 3-day mean flow, ratios of flow duration, ratios of high-flow/low-flow frequency, and coefficient of variation were used to define streamflow variability. Streamflow variability was significantly greater among the group of gaging stations located outside the Coastal Plain than among the group of gaging stations located in the Coastal Plain.

Scientific Investigations Report↗
USGS2003

Real-time surface-water monitoring in New Jersey, 2003

A network of 93 gaging stations that provide surface-water stage, flow (discharge), and tide-level data on a “realtime” basis through satellite, radio, and telephone telemetry is operating (May 2003) in New Jersey through a cooperative effort of the U.S. Geological Survey (USGS) and other agencies. The stream data from these stations are transmitted every 1 to 4 hours and then are immediately posted for viewing on the Internet. This fact sheet describes the “real-time” monitoring network, and the equipment used to measure stage and flow and to transmit the data for viewing on the Internet. Instructions for viewing the data are included.

New Jersey↗
USGS1979

Selected streamflow data for the Delaware River basin

Selected streamflow data for the Delaware River basin are given in this report. Runoff-precipitation data covering the period 1941-70 are compiled for 28 selected subbasins. Low-flow frequency curves for four main-stem Delaware River sites are also given. For Delaware River at Montague and Trenton, New Jersey, monthly comparative duration curves and 20-year hydrographs are presented in this report. Finally, flow-duration tables based on observed daily streamflow for gaging stations near 21 proposed dam sites in the Delaware River basin are given.

Delaware, New Jersey, New York, Pennsylvania↗
USGS1975

Flood of July 21, 1975 in Mercer County, New Jersey

Intense rainfall during the evening of July 20 and early morning hours of July 21, 1975 caused flooding of unprecedented magnitude in highly urbanized Mercer County, New Jersey. Over 6 inches (152 millimetres) of rainfall was recorded during a 10-hour period at Trenton, the capital of New Jersey. No lives were lost but damages to highways and bridges, to industrial, business, and residential buildings, to farmlands and crops, and to water supply systems were severe. This report illustrates the magnitude of the flood and provides hydrologic data needed for planning and design to control or lessen damages from future floods. It includes discussions of the antecedent conditions and meteorological aspects of the storm; a description of the flood and comparison to previous floods; a summary of flood stages and discharges; a discussion of flood frequency; and photomosaics which show inundated areas. More than 200 high-water marks are described as to location and elevation above mean sea level.

New Jersey↗